Efficient catalytic elimination of COS and H2S by developing ordered mesoporous carbons with versatile base N sites via a calcination induced self-assembly route

Abstract

Catalytic elimination of highly toxic COS and H2S from industrial resources plays a crucial role in terms of production safety and environmental protection. We report here novel calcination induced self-assembly concept to the fast synthesis of ordered mesoporous carbons with structural base N sites (A-N-OMC-Ts, where T stands for carbonization temperature) without using any solvent and catalysts. The A-N-OMC-Ts show large BET surface areas (∼1538 m2/g), ordered mesoporosity, and the base N sites exhibit versatile structures (e.g. pyridine and pyrrole, 2.03–3.77 wt%). As a result, A-N-OMC-Ts show excellent activities in hydrolysis of COS to H2S, and the H2S can be efficiently captured (∼10.5 mmol/g, 0 °C, 1 bar, IAST selectivity H2S/N2 = 4963, 75 °C) and oxidized into elemental sulfur by A-N-OMC-Ts. The complete elimination of COS and H2S over A-N-OMC-Ts was performed at ambient conditions (50 °C for COS; 150 °C for H2S, and Ea = 32.29 kJ/mol), much better than that of g-C3N4 (150 °C, H2S conversion < 10%, Ea = 42.11 kJ/mol). These performances are outstanding among the metal-free catalysts reported previously. A plausible mechanistic scenario involves the synergistic effect of pyridinic and pyrrolic N as well as the intermediate H2O2 was proposed by us. Coupled the cleavage of H-S bond and S release that accelerate the desulfuration rate.